Canned foods are food items that have been preserved in airtight containers, usually metal cans. This method helps to keep the food safe from bacteria and spoilage, allowing it to last for a long time without refrigeration. Common examples of canned foods include vegetables, fruits, soups, and meats. The process of canning involves cooking the food, sealing it in a can, and then heating it to kill any harmful microorganisms. This technique was developed in the early 19th century and has since become a popular way to store food for both households and emergency preparedness.